Question 10:
Diagram below shows two quadrants, AOC and EOD with centre O.
![](http://pt3mathematics.blog.onlinetuition.com.my/wp-content/uploads/sites/6/2017/12/Picture112.png)
Sector AOB and sector BOC have the same area.
Calculate the area, in cm2, of the coloured region.
Solution:
Diagram below shows two quadrants, AOC and EOD with centre O.
![](http://pt3mathematics.blog.onlinetuition.com.my/wp-content/uploads/sites/6/2017/12/Picture112.png)
Sector AOB and sector BOC have the same area.
Calculate the area, in cm2, of the coloured region.
Solution:
Question 11:
The Town Council plans to build an equilateral triangle platform in the middle of a roundabout. The diameter of circle RST is 24 m and the perpendicular distance from R to the line ST is 18 m. as shown in Diagram below.
Find the perimeter of the platform.
Solution:
![](http://pt3mathematics.blog.onlinetuition.com.my/wp-content/uploads/sites/6/2019/07/Picture125-300x300.png)
Given diameter = 24 m
hence radius = 12 m
O is the centre of the circle.
Using Pythagoras’ theorem:
The Town Council plans to build an equilateral triangle platform in the middle of a roundabout. The diameter of circle RST is 24 m and the perpendicular distance from R to the line ST is 18 m. as shown in Diagram below.
![](http://pt3mathematics.blog.onlinetuition.com.my/wp-content/uploads/sites/6/2019/07/Picture124.png)
Solution:
![](http://pt3mathematics.blog.onlinetuition.com.my/wp-content/uploads/sites/6/2019/07/Picture125-300x300.png)
Given diameter = 24 m
hence radius = 12 m
O is the centre of the circle.
Using Pythagoras’ theorem: